Help: Fix wrong return values for unset inherited properties

Since ff6234509e (Help: Clarify behavior of INHERITED properties, 2018-03-21),
the docs for some get_..._property() commands incorrectly describe
the behavior for inherited properties. When a property is not set, even
in a parent scope, the returned result from the get_..._property()
command is the same whether the property is inherited or not.
The docs incorrectly stated that an empty string would be returned
for inherited properties in such cases.

Help/command/get_source_file_property.rst

@@ -9,14 +9,12 @@ Get a property for a source file.
                            [DIRECTORY <dir> | TARGET_DIRECTORY <target>]
                            <property>)
 
-Gets a property from a source file.  The value of the property is
-stored in the specified ``<variable>``.  If the source property is not found,
-the behavior depends on whether it has been defined to be an ``INHERITED``
-property or not (see :command:`define_property`).  Non-inherited properties
-will set ``variable`` to ``NOTFOUND``, whereas inherited properties will search
-the relevant parent scope as described for the :command:`define_property`
-command and if still unable to find the property, ``variable`` will be set to
-an empty string.
+Gets a property from a source file.  The value of the property is stored in
+the specified ``<variable>``.  If the ``<file>`` is not a source file, or the
+source property is not found, ``<variable>`` will be set to ``NOTFOUND``.
+If the source property was defined to be an ``INHERITED`` property (see
+:command:`define_property`), the search will include the relevant parent
+scopes, as described for the :command:`define_property` command.
 
 By default, the source file's property will be read from the current source
 directory's scope.

Help/command/get_target_property.rst

@@ -8,13 +8,11 @@ Get a property from a target.
   get_target_property(<variable> <target> <property>)
 
 Get a property from a target.  The value of the property is stored in the
-specified ``<variable>``.  If the target property is not found, the behavior
-depends on whether it has been defined to be an ``INHERITED`` property
-or not (see :command:`define_property`).  Non-inherited properties will set
-``<variable>`` to ``<variable>-NOTFOUND``, whereas inherited properties will
-search the relevant parent scope as described for the :command:`define_property`
-command and if still unable to find the property, ``<variable>`` will be set to
-an empty string.
+specified ``<variable>``.  If the target property is not found, ``<variable>``
+will be set to ``<variable>-NOTFOUND``.  If the target property was defined to
+be an ``INHERITED`` property (see :command:`define_property`), the search will
+include the relevant parent scopes, as described for the
+:command:`define_property` command.
 
 Use :command:`set_target_properties` to set target property values.
 Properties are usually used to control how a target is built, but some

Help/command/get_test_property.rst

@@ -8,13 +8,11 @@ Get a property of the test.
   get_test_property(<test> <property> [DIRECTORY <dir>] <variable>)
 
 Get a property from the test.  The value of the property is stored in
-the specified ``<variable>``.  If the test property is not found, the behavior
-depends on whether it has been defined to be an ``INHERITED`` property
-or not (see :command:`define_property`).  Non-inherited properties will set
-``<variable>`` to ``NOTFOUND``, whereas inherited properties will search the
-relevant parent scope as described for the :command:`define_property`
-command and if still unable to find the property, ``<variable>`` will be set to
-an empty string.
+the specified ``<variable>``.  If the ``<test>`` is not defined, or the
+test property is not found, ``<variable>`` will be set to ``NOTFOUND``.
+If the test property was defined to be an ``INHERITED`` property (see
+:command:`define_property`), the search will include the relevant parent
+scopes, as described for the :command:`define_property` command.
 
 For a list of standard properties you can type
 :option:`cmake --help-property-list`.